392 resultados para inefficiency
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MAF1 is a global repressor of RNA polymerase III transcription that regulates the expression of highly abundant noncoding RNAs in response to nutrient availability and cellular stress. Thus, MAF1 function is thought to be important for metabolic economy. Here we show that a whole-body knockout of Maf1 in mice confers resistance to diet-induced obesity and nonalcoholic fatty liver disease by reducing food intake and increasing metabolic inefficiency. Energy expenditure in Maf1(-/-) mice is increased by several mechanisms. Precursor tRNA synthesis was increased in multiple tissues without significant effects on mature tRNA levels, implying increased turnover in a futile tRNA cycle. Elevated futile cycling of hepatic lipids was also observed. Metabolite profiling of the liver and skeletal muscle revealed elevated levels of many amino acids and spermidine, which links the induction of autophagy in Maf1(-/-) mice with their extended life span. The increase in spermidine was accompanied by reduced levels of nicotinamide N-methyltransferase, which promotes polyamine synthesis, enables nicotinamide salvage to regenerate NAD(+), and is associated with obesity resistance. Consistent with this, NAD(+) levels were increased in muscle. The importance of MAF1 for metabolic economy reveals the potential for MAF1 modulators to protect against obesity and its harmful consequences.
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Irrigated agriculture has come under close scrutiny in Europe recently because of its high share of total water consumption and its apparent inefficiency. Several water policies have been advocated, in particular the use of economic instruments such as water markets. This paper simulates the impact of a policy based upon water markets on agricultural production in the internal river basins of Catalonia (Spain). This zone presents certain particularities that make it very interesting to study: competition between sectors for the resource (agriculture-urban consumption-recreational uses), recent periods of resource insufficiency and conflicts between irrigators as a result of the measures taken by the hydraulic administration in drought situations. The results show that these markets would guarantee an optimal reassignment of the resource in situations of supply restrictions, and although compared to the situation without markets they would not mean higher economic profits for the irrigators, they could prevent conflicts between them. Nevertheless, doubts exist about their acceptance by irrigators
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Tutkielman tavoitteena on selvittää osakeyhtiön palkitsemisjärjestelmiin liittyviä kysymyksiä päämies–agenttisuhteiden ja osakeyhtiöoikeudellisten periaatteiden kautta. Tutkielmassa selvitetään, kuinka maksuttomia osakkeita voidaan hyödyntää julkisen osakeyhtiön palkitsemisjärjestelmissä ja mitä haasteita ja mahdollisuuksia niiden käyttöön liittyy. Tutkimusmetodi työssä on lainopillinen ja aihetta lähestytään luontevasti kauppatieteellisen ja oikeustieteellisen näkökulman yhdistävän oikeustaloustieteen kautta. Ensisijaisena aineistona tutkielmassa käytetään voimassaolevaa lainsäädäntöä valmisteluaineistoineen ja näkökulmaa syvennetään aiemmin voimassa olleen lainsäädännön tarkastelulla. Toissijaisena aineistona tutkielmassa käytetään sekä eri asiantuntijoiden oikeudellista kirjallisuutta että palkitsemisen asiantuntijoiden laatimaa kirjallisuutta Suomesta ja muista länsimaista. Teoreettista työtä on syvennetty asiantuntijahaastattelulla ja yhtiöiden sijoittajatiedosta saatavalla informaatiolla. Merkittävin osakeyhtiön johdon ja yhtiön välisen suhteen tehokkuutta alentava seikka on päämies–agenttisuhteen valvontaongelma. Tämä liittyy päämies - agenttisuhteeseen, joka ilmenee negatiivisesti yhtiön ja yhtiön johdon intressien ristiriitatilanteissa. Valvontaongelma voi aiheuttaa ylimääräisiä transaktiokustannuksia ja tämä näkyy yhtiön toiminnan tehokkuuden laskemisena. Päämies–agenttisuhteen ratkaisuna lainsäädäntö ja erilaiset valvonnan keinot ovat tehottomia ja nykyisen yhtiöoikeudellisen ajattelun vastaisia. Tehokkaimmin valvontaongelma saadaan ratkaistua erilaisin kannustimin tapahtuvalla johdon ohjauksella. Osakesidonnainen palkitseminen on suosituin johdon ja yhtiön intressien yhdistämisen keino. Osakesidonnainen palkitseminen on parhaimmillaan eri osapuolien näkökulmasta sitouttavaa ja kannustavaa mutta osakepalkitsemisen käyttöön liittyy myös riskejä. Eräs keskeisistä yhtiöoikeudellisista periaatteista on yhdenvertaisuus, jota saatetaan loukata eri palkitsemisjärjestelmiä käytettäessä. Varojen jakoon ja järjestelmien rahoitukseen liittyy niin ikään riskejä, jotka saattavat vaarantaa järjestelmän onnistumisen. Liian avokätiset palkkiojärjestelmät taas saattavat aiheuttaa yhtiön eri sidosryhmien piirissä tyytymättömyyttä joka taas alentaa järjestelmän tehokkuutta. Yhtiön johto vastaa yhtiön strategian toteutumisesta ja linjaa Corporate Governance käytännön mukaisesti johdon palkitsemisen tavat. Yhtiön johto on kuitenkin päätöksistään vastuussa yhtiön residuaalioikeuden omaaville päämiehille, eli osakkeenomistajille. Vaikka yhtiön johto vastaa viime kädessä yhtiön toiminnasta, sen on huomioitava toiminnassaan yhtiön toiminnan tarkoitus ja sitä kautta yksittäisen osakkeenomistajan etu. Vaikka osakeyhtiössä toteutettaisiin enemmistöomistajan valitsemaa toimintalinjaa, osakeyhtiön yhdenvertaisuusperiaate korostaa juuri vähemmistöosakkeenomistajan asemaa. Johdon fidusiaaristen velvoitteiden voidaankin nähdä korostuvan johdon suhteessa vähemmistöosakkeenomistajaan. Tämä on huomioitava myös palkitsemisjärjestelmissä. Johdon palkitsemisjärjestelmien suunnittelussa ja toteutuksessa on suunnattava keskeinen huomio sen tavoitteiden toteutumiseen, eli yksittäisen osakkeenomistajan omistuksen arvon kasvattamiseen pidemmällä aikavälillä, pitäen huolta osakeyhtiön kantavista periaatteista.
Resumo:
Comparison of national budgets for R&D is often made but it should consider the relative productivity and their factors. In Brazil, inefficiency factors as well as their causes have been diagnosed since the late 60's and solutions have been proposed within various governmental organisms, from CNPq to the strategy think tanks. Problems that hinder R&D and innovation in Brazil are reviewed from a historical perspective together with the proposed solutions providing a detailed analysis of the difficulties that have to be overcome to achieve a more effective innovation environment, adequate for the present times, challenges and opportunities.
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The purpose of the thesis is to analyze whether the returns of general stock market indices of Estonia, Latvia and Lithuania follow the random walk hypothesis (RWH), and in addition, whether they are consistent with the weak-form efficiency criterion. Also the existence of the day-of-the-week anomaly is examined in the same regional markets. The data consists of daily closing quotes of the OMX Tallinn, Riga and Vilnius total return indices for the sample period from January 3, 2000 to August 28, 2009. Moreover, the full sample period is also divided into two sub-periods. The RWH is tested by applying three quantitative methods (i.e. the Augmented Dickey-Fuller unit root test, serial correlation test and non-parametric runs test). Ordinary Least Squares (OLS) regression with dummy variables is employed to detect the day-of-the-week anomalies. The random walk hypothesis (RWH) is rejected in the Estonian and Lithuanian stock markets. The Latvian stock market exhibits more efficient behaviour, although some evidence of inefficiency is also found, mostly during the first sub-period from 2000 to 2004. Day-of-the-week anomalies are detected on every stock market examined, though no longer during the later sub-period.
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The objective of the study was to evaluate the effect of phosphorus on the Cd availability to plants of a contaminated soil using 109Cd isotope and chemical extractants. The experiment was set in a randomized block design and the soil was labeled with 222 KBq of 109Cd per pot and received 5 rates of P as triple superphosphate, growing lettuce plants as test crop. The use of phosphorus reduced pH of soil which altered the Cd availability in DTPA and Mehlich extractants. The lettuce Cd content decreased but its accumulation and L value increased in all treatments compared to the control, demonstrating the inefficiency of phosphorus in reducing the Cd availability.
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Polychlorinated biphenyls (PCBs) were widely used between 1940 and 1970 as an insulating fluid for transformers and capacitors. However, they are bioaccumulative and potentially carcinogenic and, according to the 2001 Stockholm Convention, must be eliminated by 2025. In Brazil, they have been gradually eliminated but contaminated equipment remains. The Brazilian official standard for PCBs content in oil analysis is the ABNT NBR 13882 and there is also the IEC 61619 International Standard, both based on GC-ECD quantification. This work identified the inefficiency of these analytical methods and highlights potential failures which generated discrepancies on quantification of these contaminants. It was observed that the IEC 61619 is superior to ABNT NBR 13882 in analytical criteria, but has problems with the inefficiency of the adsorbent material used in pretreatments for removal of oxidation products from oil where these adsorbents adsorbed some PCBs molecules, causing errors in quantification.
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Työssä pyrittiin löytämään indikaatioita markkinoiden epätehokkuudesta ja arbitraasimahdollisuuksia Suomen warranttimarkkinoilla muodostamalla osavuosikatsausten ympärille erilaisia aikaikkunoita at-the-money warranttihaaroilla. Kohde-etuutena käytettiin Nokian osaketta. Tilastollista merkitsevyyttä testattiin haarojen päivittäisistä logaritmisista tuotoista muodostetulla jakaumalla ja Excelin prosenttijärjestys() -funktiolla. Työn pohjana käytettiin McKentzien, Thomsenin ja Phelanin (2007) työtä, jossa löydettiin teurassikafutuurimarkkinoilta tilastollisesti merkitseviä tuottoja straddle-haaroilla markkinakatsausten aikana. Työssä ei löydetty tilastollisesti merkitseviä tuottoja tai tappioita pääasialli-sella merkitsevyyden mittausmenetelmällä, mutta kahdensuuntaista t-jakauman jakaumaa käyttämällä kyllä.
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Centrifugal pumps are widely used in industrial and municipal applications, and they are an important end-use application of electric energy. However, in many cases centrifugal pumps operate with a significantly lower energy efficiency than they actually could, which typically has an increasing effect on the pump energy consumption and the resulting energy costs. Typical reasons for this are the incorrect dimensioning of the pumping system components and inefficiency of the applied pump control method. Besides the increase in energy costs, an inefficient operation may increase the risk of a pump failure and thereby the maintenance costs. In the worst case, a pump failure may lead to a process shutdown accruing additional costs. Nowadays, centrifugal pumps are often controlled by adjusting their rotational speed, which affects the resulting flow rate and output pressure of the pumped fluid. Typically, the speed control is realised with a frequency converter that allows the control of the rotational speed of an induction motor. Since a frequency converter can estimate the motor rotational speed and shaft torque without external measurement sensors on the motor shaft, it also allows the development and use of sensorless methods for the estimation of the pump operation. Still today, the monitoring of pump operation is based on additional measurements and visual check-ups, which may not be applicable to determine the energy efficiency of the pump operation. This doctoral thesis concentrates on the methods that allow the use of a frequency converter as a monitoring and analysis device for a centrifugal pump. Firstly, the determination of energy-efficiency- and reliability-based limits for the recommendable operating region of a variable-speed-driven centrifugal pump is discussed with a case study for the laboratory pumping system. Then, three model-based estimation methods for the pump operating location are studied, and their accuracy is determined by laboratory tests. In addition, a novel method to detect the occurrence of cavitation or flow recirculation in a centrifugal pump by a frequency converter is introduced. Its sensitivity compared with known cavitation detection methods is evaluated, and its applicability is verified by laboratory measurements for three different pumps and by using two different frequency converters. The main focus of this thesis is on the radial flow end-suction centrifugal pumps, but the studied methods can also be feasible with mixed and axial flow centrifugal pumps, if allowed by their characteristics.
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This work investigates the Bullwhip Effect, which is one of the most important phenomena in contemporary supply chain management. The author uses most recent theoretical apparatus to analyze operational activities of a leading FMCG company British American Tobacco Eastern Europe. This paper investigates and describes the process in BAT supply chain management and considers the impact of the Bullwhip Effect together with the potential risks threatening company's operations. Emergence of the Bullwhip Effect leads to supply chain inefficiency. This paper contains methodological supply chain risk mitigation recommendations, description of a real case study and an analytical study of internal and external supply chain processes
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ABSTRACT Permanent Preservation Areas (PPAs) along watercourses have been the focus of numerous studies, not only because of the fragility and ecological relevance of riverine vegetation, but also because of the inefficiency demonstrated in conforming to the legislation protecting it. One of the major difficulties encountered in terms of guaranteeing the effective conservation of these riverside areas is the absence of methodologies that can be used to define them rapidly and accurately without manually determining the widths of the rivers or assigning only uniform linear values for the entire watercourse. The present work sought to develop a spatial analysis methodology capable of automatically defining permanent preservation areas along watercourses using geographic information system (GIS) software. The present study was undertaken in the Sergipe River basin, "considering the river itself and its principal affluents. We used the database of the Digital Atlas of Hydrological Resources (SEMARH/SE), and the delimitations of the PPAs were performed using ArcGIS 10.1 and the XToolPro 9.0 extension. A total of 5,003.82 hectares of Permanent Preservation Areas were delimited along the margins of the rivers analyzed, with a margin of error of <1% in delimiting the widths of the rivers within the entire area considered. The methodology described here can be used to define PPAs efficiently, relatively rapidly, and with very small margins of error, thus representing a technological advance in terms of using GIS for land management.
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In this study a hydrocyclone filter of 20 cm was selected and its performance was evaluated by studying the variation of discharge, pressure drop, influent concentration, and filtration efficiency with elapsed time of operation. The filter was tested with clean water to determine clean pressure drop and later it was tested with four concentrations of solid suspension, viz. 300; 600; 900 and 1,200 mg L-1. In the concentration of 300 mg L-1, the variation of pressure drop was low. But for the other concentrations of solid suspension, the variation was significant. The maximum pressure drops obtained were 41.19, 45.11, 50.01 and 52.95 kPa at 350, 390, 280 and 190 minutes of elapsed time, respectively. The maximum efficiency of solid suspension was 30.3, 32.96, 43.89 and 52.5% where as the minimum efficiencies were 9.91, 9.93, 9.62 and 9.9%, respectively. The hydrociclone tested presented inefficiency to filter small particles as clay. The initial removal efficiency of higher concentration was bigger than for lower concentration but, the final efficiency are almost the same irrespective of the concentration of solid suspension. The present tested hydrocyclone could be used as a pre-filter microirrigation to prevent emitter clogging.
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Tutkielmassa käsitellään markkina- ja sääntelyhäiriötä ja keskitytään selittämään, millä tavoin nämä häiriöt aiheuttavat taloudellista tehottomuutta. Lisäksi työssä osoitetaan markkina- ja sääntelyhäiriöiden välinen yhteys ja selitetään, kuinka markkina- ja sääntelyhäiriöiden ilmenemistä voitaisiin vähentää.
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The oxidation potential of pulsed corona discharge concerning aqueous impurities is limited in respect to certain refractory compounds. This may be enhanced in combination of the discharge with catalysis/photocatalysis as developed in homogeneous gas-phase reactions. The objective of the work consists of testing the hypothesis of oxidation potential enhancement in combination of the discharge with TiO2 photocatalysis applied to aqueous solutions of refractory oxalate. Meglumine acridone acetate was included for meeting the practical needs. The experimental research was undertaken into oxidation of aqueous solutions under conditions of various target pollutant concentrations, pH and the pulse repetition rate with plain electrodes and the electrodes with TiO2 attached to their surface. The results showed no positive influence of the photocatalyst, the pollutants were oxidized with the rate identical within the accuracy of measurements. The possible explanation for the observed inefficiency may include low UV irradiance, screening effect of water and generally low oxidation rate in photocatalytic reactions. Further studies might include combination of electric discharge with ozone decomposition/radical formation catalysts.
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Weed resistance to herbicides has been a major issue in Brazil, mainly due to the inefficiency of the herbicides used in no-till areas and to the high cost of these herbicide treatments. Failures in controlling the weed Conyza have been reported in Western and Northern grain crop areas in Paraná (Brazil). This work aimed to evaluate the potential occurrence of C. sumatrensis biotypes resistant to the herbicides chlorimuron-ethyl and glyphosate. Experiments were carried out under greenhouse conditions with four biotypes (Cascavel-2, Toledo-4, Tupãssi-6, and Assis Chateaubriand-7) possibly resistant to, as well as a population considered susceptible to chlorimuron-ethyl and glyphosate. To obtain dose-response curves, eight herbicide doses of chlorimuron-ethyl (0, 2.5, 5, 10, 20, 40, 80 and 160 g ha-1) and glyphosate (0, 90, 180, 360, 720, 1,440, 2,880 and 5,760 g e.a. ha-1) were applied and weed control and shoot biomass evaluations were made. Results provided evidence that two biotypes (Cascavel-2 and Tupãssi-6) were resistant to glyphosate and four biotypes (Cascavel-2, Toledo-4, Tupãssi-6 and Assis Chateaubriand-7) were resistant to chlorimuronethyl. Multiple resistance to glyphosate and chlorimuron was confirmed for biotypes Cascavel2 and Tupãssi 6. This is the first report on multiple resistance in Conyza sumatrensis, worldwide.